Manitoba Airbrake Practice Exam

At what PSI level must the low pressure warning device activate?

1. 55 psi

2. 60 psi

3. 45 psi

4. 70 psi

The correct answer is: 55 psi

The low pressure warning device must activate at 55 psi because it is the required minimum pressure level to ensure safe operation of the vehicle. Option B, 60 psi, is slightly higher than the minimum requirement and may not provide enough warning to the driver. Option C, 45 psi, is below the minimum requirement and could result in an unsafe situation if the driver is not notified of low pressure. Option D, 70 psi, is above the minimum requirement and may not activate the warning device until the pressure has dropped to a dangerous level. Therefore, option A, 55 psi, is the best choice to ensure proper functionality of the low pressure warning device and maintain safe operation of the vehicle.